Gas turbine engines may typically include a compressor, a combustor, and a turbine, with an annular flow path extending axially through each. Air flows through the compressor where it is compressed or pressurized. The combustor then mixes and ignites the compressed air with fuel, generating hot combustion gases. These hot combustion gases are then directed from the combustor to the turbine where power is extracted from the hot gases by causing blades of the turbine to rotate.
The compressor and turbine sections of the engine include airfoil arrays, such as multiple alternating stages of rotor blades and stator vanes. These airfoil arrays may include features, such as endwall contouring, cored serpentine passages, cross-platform serpentine passages, and the like, to mitigate endwall losses, cool the platforms from which the airfoils extend, and better enhance the overall performance of the engine. In addition, durability coatings may be applied to the airfoil arrays to prevent accelerated material deterioration.
In order to reduce costs, airfoil arrays are cast in clusters having two or more airfoils. However, applying durability coatings to airfoil clusters after casting may be difficult. This invention is directed to providing a reliable method for facilitating the application of durability coatings to airfoil clusters, while taking into consideration features, such as endwall contouring and serpentine passages.